Transmissible spongiform encephalopathies (TSEs) or prion diseases, are neurodegenerative diseases of conformation in which the cellular prion protein (PrPC) misassembles into an abnormal conformer (PrPSc). PrPSc is thought to be the sole constituent of infectious prion particles. Prion propagation proceeds via a highly-specific process of conformational rearrangement in which PrPSc imposes its own structure upon PrPC bound to it. The transmission of bovine spongiform encephalopathy prions to humans, manifesting clinically as variant Creutzfeldt-Jacob disease, and ongoing spread of chronic wasting disease in cervids in North America, have demonstrated the pressing need for effective prion therapeutics. In this proposal we have developed experimental strategies designed to yield small molecule inhibitors of prion propagation suitable for use in the prevention and/or therapy of prion infection and disease. Two distinct approaches have been taken. In the first, drawing upon our considerable experience using PrP-specific antibodies, we seek to identify small compounds binding specifically to key regions of either PrPC or PrPSc. We hypothesize that molecules preventing PrPC-PrPSc interactions will effectively inhibit assembly of the prion replicative complex, preventing generation of nascent prion infectivity. In a second approach, small molecules binding specifically to PrPC, increasing the intrinsic thermodynamic and kinetic stability of this molecule and thereby precluding the possibility of unwanted conformational changes that are intimately associated with prion pathogenesis and PrPSc formation will be identified. Molecules recovered via both of these strategies will be evaluated for their capacity to resolve prion infection in vitro and in vivo.